Objective  To establish an animal model of human parainfluenza virus type 3 (HPIV3) infection in mice, and characterize the immune responses of the HPIV3 infected mice. Methods  BALB/c mice were infected intranasally with wild strain HPIV3LZ1728C19 isolated from clinical specimens. The body mass and temperature of infected mice were measured daily for 30 d. The titers of HPIV3-specific IgG and IgA in serum were detected by ELISA, and the viral titer in nasal lavage and lung tissue were detected by quantitative real-time PCR. The HPIV3-specific IgG and IgA antibody secreting cells (ASCs) and the HPIV3-specific IFN-γ CD4⁺/CD8⁺ T cell in lymphocytes isolated from lung, spleen and peripheral blood were detected by enzyme-linked immunospot assay and flow cytometry, respectively. The pathological changes in lung tissue were observed by lung slice. Results  The HPIV3 replicated and viral loads peaked (10⁴ copies/ml nasal lavage and 10⁷ copies/g lung tissue) at post infection day 3 (PID3) in infected mice. HPIV3 infection significantly affected the body mass gain of mice at early stage of infection (t=4.64,P<0.05 at PID3), and resulted in inflammatory pathological changes in lung tissue. The HPIV3 specific IgG (t=2.94,P<0.05) and IgA (t=18.66,P<0.05) antibody levels were significantly higher in infected mice serum than control, with virus-specific ASC responses in all 3 kinds of tissues. Virus infection induced HPIV3-specific IFN-γ CD8⁺ T cell response in lung, and HPIV3-specific IFN-γ CD4⁺ T cells response in spleen and peripheral blood. Conclusions  A mouse model of HPIV3 infection is successfully established. Lung mucosal humoral and cellular immune responses are induced in BALB/c mice infected intranasally with HPIV3.